1. Field of the Invention
The present invention relates to an electroluminescent device, and more particularly, to an electroluminescent display panel, in which an operation of an electroluminescent device is controlled, for fabricating a high definition display; and a method for operating the same.
2. Background of the Related Art
The electroluminescent device has been given attention as a next generation flat display because in comparison with a passive device which requires reception of light for displaying a picture, the electroluminescent device has advantages of a fast response speed, an excellent luminance as it is an active device, a simple structure permitting easy fabrication, light weight, and a thin and compact size.
The electroluminescent device has a wide variety of applications, such as liquid crystal display (LCD_ back lights, mobile stations, car navigation systems (CNS), notebook computers, and wall mounting type television (TV) sets.
In the electroluminescent device, there are inorganic electroluminescent devices, and organic electroluminescent devices according to a material of the electroluminescent device.
The organic electroluminescent device is a device in which a charge is injected into an organic thin layer between an electron injected electrode and a hole injected electrode, to form one pair of an electron and a hole, which collapse to emit light. The inorganic electroluminescent device is a device in which an electron accelerated by a strong field is collided with a luminescent material, to excite the luminescent material, and to make the luminescent material luminescent as the luminescent material drops down to a base state.
A related art electroluminescent display panel will be explained. FIG. 1 illustrates a circuit of unit pixel of a related art electroluminescent display panel.
Referring to FIG. 1, the unit pixel is provided with first and second switching devices 11 and 13 connected to a sourceline SL in series for switching a data signal in response to a signal applied to a gateline GL, a capacitor 15 having a first terminal connected to an output terminal of the second switching device 13, a second terminal connected to a power source terminal Vdd, for having a data voltage received through the first and second switching devices 11 and 13 charged thereto, a third switching device 17 connected between an output terminal of the first switching device 11 and the second terminal of the capacitor 15, to be controllable by the voltage induced at the first terminal of the capacitor 15, and a fourth switching device 19 connected between the power source terminal Vdd and a electroluminescent device 20, to be switchable by a voltage induced at the first terminal. The first to fourth switching devices 11, 13, 17, and 19 are PMOS transistors.
The operation of the related art electroluminescent display panel will be explained.
When an enable signal is provided to the gateline GL, and a sink current is provided to the sourceline SL, a data voltage pertinent to the signal is charged to the capacitor 15 through first and second switching devices 11 and 13.
Next, a current pertinent to the current through the third switching device 17 is provided to the electroluminescent device 20 through the fourth switching device 19, to make the electroluminescent device luminescent for a certain time period.
Thereafter, even if the gate signal that controls the first and second switching devices 11 and 13 is cut, the electroluminescent device remains luminescent as the data voltage stored in the capacitor is discharged.
However, the related art electroluminescent display panel has the following problems.
Pixel sourcelines running throughout the entire region of the electroluminescent display panel have resistance components, and there are parasitic capacitors between the gatelines and the sourcelines, resulting in requiring a long time for storing the data voltage to the capacitor 15 if a weak sink current flows to the sourceline SL to provide a data voltage pertinent to the weak sink current, in the present frame after a prior frame is finished. Accordingly, as shown in FIG. 2, blurring of the picture occurs in the present frame 2f after the prior frame is finished, which hinders fabrication of high definition of the electroluminescent display panel.